Surface guide
QR codes on digital signage
Digital signage QR codes follow the same ten-to-one rule as print — 10–30 cm for a 1–3 m viewing distance — with two screen-specific problems: dwell time in the playlist, and glare from ambient lighting.
| Typical scan distance | 1–3 m |
|---|---|
| Minimum code width | 10–30 cm |
| Error correction | M |
Playlist dwell time
A ten-second slot is not enough. The viewer must notice the code, decide to act, get their phone out and frame it. Twenty to thirty seconds for a slide carrying a code, and it should be the last thing on the slide so it is still there while they fumble.
Glare
A screen in a bright mall or a sunlit window reflects everything. Matt anti-glare panels are worth the extra cost wherever the code matters. Raising brightness helps less than reducing reflection.
Brightness and contrast
Do not use a mid-grey background thinking it looks softer. Pure white background, pure black modules. Screens have huge dynamic range and there is no reason to spend any of it.
Height and angle
Centre the code at 1.4–1.6 m. Screens mounted high, angled down, are scanned at steep angles where decoding degrades quickly.
Refresh and burn-in
On OLED signage, a static code left permanently in the same position risks image retention. Move it a few pixels between loops, or vary its position between slides.